Anticoagulation and atrial fibrillation – more action, less anxiety

Domhnall MacAuley is a CMAJ Associate Editor and a professor of primary care in Northern Ireland, UK

Atrial fibrillation makes me nervous. In the distant past there was only digoxin. Later, we debated the merits of focusing on rhythm vs. rate and we checked digoxin levels but, for the most part, it was a hospital topic. Yet as evidence mounted on the risks of stroke, the responsibility for managing atrial fibrillation began to migrate into primary care. Detecting, treating and anticoagulating became more important. Checking the pulse was much more than a ritual - it could be a life saver.

Anticoagulation also makes me nervous. Warfarin is straightforward in theory but patients don’t tend to follow textbook models. There is always debate about the optimal starting regime and strategies for monitoring. Computer programmes make it easier but there are always rogue results, patients with odd INR patterns and, even more worrying, those who don’t turn up for testing.

Doctors and patients may have been even more concerned by reports in the New York Times citing two recent papers from the NEJM indicating that many strokes of unknown aetiology may be due to undetected atrial fibrillation. One of the these studies was the Embrace trial, based on the Canadian Stroke Network, with collaborating centres across Canada. They found that, in those with a recent cryptogenic stroke or TIA who were 55 years of age or older, paroxysmal atrial fibrillation was common. Their findings, that “noninvasive ambulatory ECG monitoring for a target of 30 days significantly improved the detection of atrial fibrillation by a factor of more than five and nearly doubled the rate of anticoagulant treatment, as compared with the standard practice of short-duration ECG monitoring” has suddenly made follow up more complex. This is backed up by a study from Italy suggesting longer post stroke monitoring. By this time, of course, most of these patients should be back in the community under the care of their family doctors. On a more positive note, however, the UK National Institute of Clinical Excellence (NICE) recently recommended more frequent use of the newer anticoagulants that don’t require regular monitoring.